Reptiles/Transcript
Transcript Old Version Text reads: The Mysteries of Life with Tim and Moby Update Text reads: The Mysteries of Life with Cassie and Moby Moby is watching a video entitled, Elephant vs. Snake, on a laptop computer. An elephant trumpets repeatedly as an anaconda wraps itself around the elephant. Moby looks terrified as he watches the video. Cassie enters Moby's room. CASSIE: Hey! How's the exposure therapy coming? Moby pauses the video and looks at her, uneasy. MOBY: Beep. CASSIE: You'll never get over your fear of snakes from watching fake videos. Cassie reads from a typed letter. CASSIE: Dear Cassie and Moby, will you do a movie on reptiles? Thanks, Keith. Hey, Keith! There are thousands and thousands of reptile species. Images show a variety of snakes, lizards, and turtles. CASSIE: They live on land and in the water pretty much everywhere except Antarctica. A world map indicates there is reptile life on six of the seven continents. CASSIE: A lot of them look way different from each other, but they all share some common features. You know you're looking at a reptile when it's covered in these tough scales. That skin protects them, and keeps moisture inside. An animation shows a lizard sitting on a rock. Its large neck-sack inflates. A close-up of its skin shows the type of scales Cassie describes. CASSIE: Most reptiles regularly molt, or shed their skin, to grow. An animation shows a snake moving along a tree branch. Friction from the movement pulls a layer of dead skin from the snake. MOBY: Beep. CASSIE: Actually, people shed their skin, too, just a tiny bit at a time. And that's not all we have in common with reptiles. An image shows a Venn diagram with a person in the left circle, reptiles in the right circle, and an image of shed skin in the center where the circles overlap. CASSIE: They're vertebrates, meaning they have a backbone. And they all have a pair of lungs to breathe air, even sea turtles and snakes. Images of a backbone and lungs appear in the center of the Venn diagram. MOBY: Beep. CASSIE: That's about where the similarities end. Most reptiles are ectothermic, or cold-blooded. They can't produce their own body heat, so they get it from the sun. An animation shows three iguanas, sitting on rocks overlooking the ocean, taking in heat from the sunlight. CASSIE: And unlike mammals, they hatch from leathery eggs. An animation shows baby sea turtles hatching from leathery eggs on a sandy beach and crawling away. CASSIE: Baby reptiles are basically just mini versions of adults. They're ready to fend for themselves right out of the egg. Which is a good thing, because the parents are usually long gone by then. An animation shows a baby alligator hatching and crawling across a patch of grass. CASSIE: Some snakes hatch inside the mother's body, and are born alive! But even then, the mother doesn't need to stick around and care for them. An animation shows several baby snakes slithering out of their mother as she crawls off. MOBY: Beep. Cassie and Moby are watching the animations on Moby's laptop. Moby looks as if he is going to be sick. CASSIE: Reptiles mainly fall into one of four categories. Lizards are the most diverse, with over 4,000 different species. An image shows several lizards of various sizes and species. CASSIE: The majority are omnivores, feeding on both plants and animals. Most species eat insects and other bugs. An animation shows a lizard in a desert, catching small flying insects with its tongue. CASSIE: But big guys like this monitor lizard feed on mammals and birds, too. An animation shows a large monitor lizard walking in a jungle. A small, white bunny hops by, ignored by the lizard. CASSIE: Lizards usually have four legs with sharp-clawed feet. And their bodies generally taper off into tails. Two close-ups show the claws on a monitor lizard's foot and its tail. MOBY: Beep. Moby is watching the lizard animations on his laptop. CASSIE: Oh, right, that's another really cool thing! A lot of lizards can flick out their tongues to smell their surroundings. An animation shows a monitor lizard flicking out its forked tongue. CASSIE: The tongue is collecting airborne molecules and bringing them back into the Jacobson's organ inside its mouth. An animated close-up illustrates the process Cassie describes. Additional animation shows the appearance and location of the monitor lizard's Jacobson's organ, which is in the roof of the lizard's mouth, beneath its nose. MOBY: Beep. CASSIE: Yep, all snakes do exactly the same thing. Their forked tongues are built to deliver scents right to the Jacobson's organ. Images show four different kinds of snake, each with its forked tongue extended. CASSIE: After lizards, snakes are the second most common type of reptile. They have no limbs and live just about everywhere on Earth, including the oceans! An animation shows a snake swimming beneath the surface of an ocean. CASSIE: All snakes are carnivorous, consuming only meat, and sometimes eggs. They can unlatch their jaws to swallow stuff that's bigger than their own heads! An animation shows a snake swallowing an egg, as Cassie describes. CASSIE: Only a few snakes are poisonous, by the way; most are harmless to people. MOBY: Beep. CASSIE: Okay, okay, let's move on to something cuter. Turtles and tortoises can live on land, in fresh water, or in the sea. Animations show turtles and tortoises living in these three environments. CASSIE: All of them have protective shells. Some can pull their heads and limbs inside when the going gets tough. An animation shows a turtle on a log in fresh water. It retracts its head and limbs as Cassie describes. CASSIE: Unlike other types of reptiles, turtles and tortoises have no teeth. Instead, they have beaks that help them bite off food and chew it. The turtle extends its head and yawns loudly, displaying its beak. CASSIE: Crocodilians, on the other hand, do have teeth… lots of them! An animation shows a crocodile, lying motionless on its stomach. Its mouth is open wide, with several teeth on display. A bird is perched in its mouth, cleaning the crocodile's teeth. The bird finishes and walks off. CASSIE: Besides crocodiles, they include alligators and caimans, too. Images show a crocodile, an alligator, and a caiman. CASSIE: All crocodilians are carnivorous, and they live mainly in the tropics. An animation shows a crocodile sunning itself on the shore of a lagoon. CASSIE: Most of their time is spent in the water, so they've evolved some nifty adaptations for hunting. Like eyes and nostrils on the tops of their heads. That lets them see and breathe while they stay hidden under the surface. An animation shows a crocodile swimming underwater. While still submerged, it spots a deer eating on the shore. It approaches the deer, unseen. MOBY: Beep. CASSIE: Yeah, they kind of do look like dinosaurs! Which shouldn't be too big a surprise: dinosaurs were reptiles, too. The image of the crocodile is shown next to a dinosaur. The dinosaur roars. CASSIE: More than 300 million years ago, reptiles were the first vertebrates to leave the water behind and live entirely on land. An animation shows a reptile crawling from the water and evolving into a creature living on land. CASSIE: As they spread out and adapted to new environments, they became more diverse. One branch evolved into dinosaurs, which all modern birds are descended from. An animated diagram depicts the evolution of dinosaurs to modern birds. CASSIE: Another branch of reptiles became mammals. Another branch appears on the diagram, showing the reptile evolving into mammals like a man, a seal, and a fox. CASSIE: And the rest evolved into modern snakes, lizards, crocs, and turtles. Additional branches appear on the diagram, illustrating how the reptile evolved into the other animals Cassie names. CASSIE: Today, pretty much every vertebrate on land has a reptile somewhere back in its family tree. That's why we all share so many things in common. The Venn diagram from earlier appears. A third overlapping circle is added for the birds, and the seal and the fox are added to the mammals circle with the man in it. They all share a backbone, shedding skin, and lungs with the reptiles in the third circle. CASSIE: Anyway, I hope this has helped you get over your fear of snakes. MOBY: Beep. Moby smiles and gives a thumb's-up. CASSIE: Hey, I'm proud of you! You deserve a Moby snack! Cassie hands Moby a can labeled, Moby Snax. MOBY: Beep. Moby takes the can and opens it. Fake snakes spring out of the can in all directions. He runs out of the room in terror, bursting through the closed door. CASSIE: Ain't I a stinker? Category:BrainPOP Transcripts